It is hard to understand a person! Asked Amber before, is it possible to know a person completely? The answer is no. You will not never know completely what a person is thinking also,why?
Because people change from time to time.
Changed in mindset, changed in the way you do things, changed in the way you present yourself, changed in the focus in life, changed by the things happening around, etc etc.
The music that you listen to, the way you walk, the way you talk, your body language, your face features, your doodling, your dressing style, your hand writing and everything else that is related to you reflects hidden parts of your personality.

To understand others we must apply this quote in our priorities:

The least important word: I
The most important word: We
The two most important word: Thank you
The three most important word: All is forgiven
The four most important word: What is your opinion?
The five most important word: You did a good job.
The six most important word: I want to understand you better.

To foster understanding, think of what your emotions would be if you were in the same position as the person you're interacting with.Knowing what the people need and want is the key to understanding them!

Hope i can understand better!=)